It is known from U.S. Pat. No. 5,408,403, assigned to the present assignee, to employ a ballast for a gas discharge lamp incorporating a d.c.-to-a.c. converter using a pair of serially connected converter switches. A boost circuit is incorporated into the ballast to achieve a high degree of power factor correction. However, the converter switches are both of the same conduction type; e.g., both n-channel enhancement mode MOSFETs.
A lamp ballast incorporating a d.c.-to-a.c. converter using serially connected switches of complementary conduction types is disclosed and claimed in co-pending and commonly assigned application Ser. No. 08/709,062, filed Sep. 6, 1996, by Louis R. Nerone, one of the present inventors. For instance, one switch may be an n-channel enhancement mode MOSFET, while the other is a p-channel enhancement mode MOSFET.
It would be desirable to increase power factor correction in a ballast incorporating a d.c.-to-a.c. converter using switches of the same conduction type.